rs2197076 — FABP1

Intronic FABP1 variant associated with type 2 diabetes risk and insulin resistance; likely tags the functional haplotype containing the T94A missense in the liver fatty acid transport protein

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FABP1 rs2197076 — An Intronic Marker in the Liver Fatty Acid Transport Gene

FABP1 (Fatty Acid Binding Protein 1), also called L-FABP or liver FABP, is the most abundant cytosolic protein in human hepatocytes. It binds long-chain fatty acids, bile acids, and other hydrophobic ligands and shuttles them from the plasma membrane to the endoplasmic reticulum and mitochondria for esterification and oxidation11 FABP1 constitutes roughly 3-5% of total cytosolic protein in the adult human liver; its extraordinary abundance reflects the hepatocyte's central role in whole-body lipid homeostasis. By modulating the intracellular concentration of free fatty acids, FABP1 directly influences hepatic triglyceride synthesis, VLDL secretion, and fat oxidation.

rs2197076 is a G>A intronic variant in FABP1 (GRCh38: chr2:88,123,239; NM_001443.3:c.334-135C>T in coding-strand notation — the gene sits on the minus strand, so the plus-strand reference is G and the alternate is A). The variant does not alter the FABP1 protein sequence; its clinical relevance lies in its association with diabetes and metabolic risk phenotypes, and in its position within the same haplotype block as the T94A missense variant (rs2241883)22 T94A missense variant (rs2241883)
rs2241883 is a coding variant in FABP1 that substitutes alanine for threonine at position 94 of the protein; this structural change reduces the protein's fatty acid binding affinity and has been independently linked to elevated triglycerides, LDL, and NAFLD risk.

The Mechanism

As an intronic variant, rs2197076 does not directly alter FABP1 protein function. Its biological significance is likely one of two types: it may influence the transcriptional regulation of FABP1 — reducing hepatic FABP1 expression so that fewer binding sites are available for incoming fatty acids — or it may serve as a tag SNP33 tag SNP
A tag SNP is in linkage disequilibrium with one or more functional variants in the same haplotype block; the tag SNP itself may be functionally neutral, but its presence reliably predicts the presence of the functional allele elsewhere on the chromosome marking the T94A haplotype.

The liver FABP1 protein binds two fatty acid molecules simultaneously — a unique feature among the FABP family — enabling high-flux lipid transport in hepatocytes that process a continuous dietary fat load. When FABP1 is reduced or its binding affinity is impaired, free long-chain fatty acids accumulate in the cytosol, activate nuclear receptors differently, and may increase hepatic lipid deposition, triglyceride synthesis, and insulin resistance signaling. The A allele of rs2197076 is the minor allele in African and European populations (~9–18%) but approaches or exceeds 50% in East and South Asian populations, making it a particularly relevant variant for those ancestries.

The Evidence

The primary evidence for rs2197076 comes from a Spanish population study by Mansego et al.44 Spanish population study by Mansego et al.
Mansego ML et al. Common variants of the liver fatty acid binding protein gene influence the risk of type 2 diabetes and insulin resistance in Spanish population. PLoS One 2012 that examined 1,217 participants in an original cohort and replicated findings in 805 Segovia subjects. rs2197076 was the only single SNP in FABP1 to reach strong association with type 2 diabetes risk in both cohorts, and FABP1 haplotypes containing this variant also associated with HOMA-IR (a direct index of insulin resistance). No FABP2, FABP3, or FABP4 variants showed similar associations in the same study.

Two studies in polycystic ovary syndrome provide convergent evidence. Xue et al. 201655 Xue et al. 2016
Xue H et al. Association of SNPs rs2197076 and rs2241883 of FABP1 gene with PCOS. J Assist Reprod Genet 2016 genotyped both rs2197076 and the T94A coding variant in 221 Chinese PCOS women and 198 controls, finding P<0.001 for allele frequency differences; rs2197076 associated more strongly with core PCOS features than rs2241883, suggesting an independent regulatory contribution. Rashid et al. 201766 Rashid et al. 2017
Rashid N et al. Association of IL-1β, IL-1Ra and FABP1 gene polymorphisms with metabolic features of PCOS. Inflamm Res 2017 confirmed that the A allele specifically correlated with dyslipidemia and cardiovascular risk biomarkers in PCOS patients.

Mechanistic context for the haplotype is provided by studies of the T94A coding variant (rs2241883). Schroeder et al. 201677 Schroeder et al. 2016
Schroeder F et al. Fatty acid binding protein-1 and the human FABP1 T94A variant: roles in the endocannabinoid system and dyslipidemias. Lipids 2016 reviewed evidence that T94A expression in males increases hepatic triglycerides and cholesteryl esters through disrupted endocannabinoid enzyme transcription. The T94A variant also shows sex-dependent effects — female carriers exhibit compensatory metabolic adjustments that limit lipid accumulation relative to males. Whether rs2197076 tracks these effects independently or entirely through LD with rs2241883 is not yet resolved, but the combined evidence positions the FABP1 locus as a genuine metabolic risk factor, particularly for individuals of East and South Asian ancestry where the A allele is common.

The overall evidence supports a moderate rating: findings are replicated across three independent studies but remain confined to relatively small cohorts and specific populations, with no large GWAS signal or clinical-grade guideline.

Practical Actions

For A-allele carriers, the key leverage points are dietary fat quality, hepatic biomarker monitoring, and awareness of insulin resistance risk. Since FABP1 handles the intracellular distribution of fatty acids in the liver, the composition of dietary fat matters: saturated and trans fats promote hepatic triglyceride accumulation, while long-chain omega-3 fatty acids (EPA/DHA) activate hepatic PPARα and reduce triglyceride synthesis. Monitoring fasting triglycerides and glucose provides an early window into whether FABP1 haplotype variation is expressing itself metabolically.

Interactions

rs2197076 is physically close to and likely in partial linkage disequilibrium with rs2241883 (T94A), the missense variant in FABP1 exon 3. Both SNPs have been studied together in PCOS cohorts. The T94A missense has independent literature supporting its effect on lipid metabolism and NAFLD. If you carry risk alleles at both rs2197076 and rs2241883, the combined FABP1 haplotype may represent greater impairment of hepatic fatty acid handling than either SNP alone, though no published study has formally quantified a compound effect.

The FABP1 locus also intersects with dietary fat intake: the variant's metabolic effects are more pronounced in high-fat dietary contexts where hepatic FABP1 is under greatest demand. Individuals with FABP family risk variants (including FABP2 Ala54Thr, rs1799883) may carry compound metabolic fatty acid handling burden across intestinal absorption and hepatic transport.

Nutrient Interactions

long-chain fatty acids altered_metabolism
dietary fat altered_metabolism

Genotype Interpretations

What each possible genotype means for this variant.

GG Common Genotype Normal

Common FABP1 intronic genotype — no elevated metabolic risk at this locus

The G allele is the GRCh38 plus-strand reference allele at chr2:88,123,239 and the major allele in European (~82%) and African (~91%) populations. GG individuals represent the lower end of FABP1 haplotype-associated metabolic risk. Note that in East and South Asian populations, G is actually the minor allele (~49% and ~56% respectively), so GG is relatively uncommon in those ancestries. No elevated risk for type 2 diabetes, insulin resistance, or dyslipidemia has been attributed to the GG genotype.

AG Intermediate

One A allele at FABP1 rs2197076 — modest elevated risk for insulin resistance

rs2197076 was studied under an additive inheritance model by Mansego et al. 2012, meaning each A allele contributes incrementally to metabolic risk. AG carriers therefore sit between GG (baseline) and AA (highest risk) in terms of the association signal. The A allele's mechanism is likely regulatory — reducing FABP1 hepatic expression or tagging the T94A missense (rs2241883) haplotype, which structurally impairs fatty acid binding affinity. Both mechanisms converge on reduced intracellular fatty acid transport efficiency in the liver, promoting hepatic lipid accumulation and insulin resistance under high dietary fat load.

AA High Risk

Two A alleles at FABP1 rs2197076 — highest risk for type 2 diabetes and dyslipidemia at this locus

AA homozygosity places you at the high end of the FABP1 rs2197076 association with type 2 diabetes and insulin resistance. Mansego et al. 2012 demonstrated this association across two independent Spanish populations, and Rashid et al. 2017 specifically identified the A allele with dyslipidemia and cardiovascular risk biomarkers in PCOS patients. The biological reasoning is that this haplotype either reduces hepatic FABP1 expression (reducing the liver's capacity to safely sequester and process incoming dietary fatty acids) or tags the T94A missense variant (rs2241883) that structurally impairs fatty acid binding affinity. Either mechanism leads to elevated cytosolic free fatty acid concentrations, which drive hepatic triglyceride synthesis, VLDL overproduction, insulin resistance signaling, and increased cardiovascular risk.

The sex-dependent effects seen for the nearby T94A missense — where male carriers accumulate more hepatic lipid than female carriers due to different endocannabinoid compensation — may also apply to this haplotype, though this has not been directly tested for rs2197076 AA specifically.